With the increasing use of smartphones and tablets by large corporations and defense agencies, there is increasing concern about the security of such devices. The US Department of Defense, in particular, is interested in actively authenticating mobile device users. This desire arises in part because of the ineffectiveness of passwords and in part because the device may change hands after the rightful owner has unlocked it. There is a need, then, to authenticate the user of a mobile device as it is being used for its intended purpose.
In one prior device, a user may unlock a phone by gazing at images in a specified sequence. The device is unlocked when eye tracking data matches expected eye tracking data. One prior device purports to track a user's eyes to determine where to scroll. When a user reads text, and eye tracking indicates the last text on the page has been read, the next page of text may be automatically displayed.